wikimedia/mediawiki-core

<?php
/**
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 */

use MediaWiki\Languages\LanguageFactory;

/**
 * Collation that orders text with numbers "naturally", so that 'Foo 1' < 'Foo 2' < 'Foo 12'.
 *
 * Note that this only works in terms of sequences of digits, and the behavior for decimal fractions
 * or pretty-formatted numbers may be unexpected.
 *
 * Digits will be based on the wiki's content language settings. If
 * you change the content language of a wiki you will need to run
 * updateCollation.php --force. Only English (ASCII 0-9) and the
 * localized version will be counted. Localized digits from other languages
 * or weird unicode digit equivalents (e.g. ４, 𝟜, ⓸ , ⁴, etc) will not count.
 *
 * @since 1.28
 */
class NumericUppercaseCollation extends UppercaseCollation {

    /**
     * @var Language How to convert digits (usually the content language)
     */
    private $digitTransformLang;

    /**
     * @param LanguageFactory $languageFactory
     * @param string|Language $digitTransformLang How to convert digits.
     *  For example, if given language "my" than ၇ is treated like 7.
     *  It is expected that usually this is given the content language.
     */
    public function __construct(
        LanguageFactory $languageFactory,
        $digitTransformLang
    ) {
        $this->digitTransformLang = $digitTransformLang instanceof Language
            ? $digitTransformLang
            : $languageFactory->getLanguage( $digitTransformLang );
        parent::__construct( $languageFactory );
    }

    public function getSortKey( $string ) {
        $sortkey = parent::getSortKey( $string );
        $sortkey = $this->convertDigits( $sortkey );
        // For each sequence of digits, insert the digit '0' and then the length of the sequence
        // (encoded in two bytes) before it. That's all folks, it sorts correctly now! The '0' ensures
        // correct position (where digits would normally sort), then the length will be compared putting
        // shorter numbers before longer ones; if identical, then the characters will be compared, which
        // generates the correct results for numbers of equal length.
        $sortkey = preg_replace_callback( '/\d+/', static function ( $matches ) {
            // Strip any leading zeros
            $number = ltrim( $matches[0], '0' );
            $len = strlen( $number );
            // This allows sequences of up to 65536 numeric characters to be handled correctly. One byte
            // would allow only for 256, which doesn't feel future-proof.
            $prefix = chr( (int)floor( $len / 256 ) ) . chr( $len % 256 );
            return '0' . $prefix . $number;
        }, $sortkey );

        return $sortkey;
    }

    /**
     * Convert localized digits to english digits.
     *
     * based on Language::parseFormattedNumber but without commas.
     *
     * @param string $string sortkey to unlocalize digits of
     * @return string Sortkey with all localized digits replaced with ASCII digits.
     */
    private function convertDigits( $string ) {
        $table = $this->digitTransformLang->digitTransformTable();
        if ( $table ) {
            $table = array_filter( $table );
            $flipped = array_flip( $table );
            // Some languages seem to also have commas in this table.
            $flipped = array_filter( $flipped, 'is_numeric' );
            $string = strtr( $string, $flipped );
        }
        return $string;
    }

    public function getFirstLetter( $string ) {
        $convertedString = $this->convertDigits( $string );

        if ( preg_match( '/^\d/', $convertedString ) ) {
            return wfMessage( 'category-header-numerals' )
                ->numParams( 0, 9 )
                ->text();
        } else {
            return parent::getFirstLetter( $string );
        }
    }
}